Process of recovering uranium



Oct. 7, 1958 J'. M. CARTER ETAL 2,855,270

PROCESS OF RECOVERING URANIUM 5 Slieets-Sheet 1 Filed Oct. 20, 1944 s WY T A Nrn R EEO w M Cm. 3 m JC Oct. 7, 1958 3119a Oct. 20. 1944 .1. M.CARTER ETAL PROCESS OF RECOVERING URANIUM 5 Sheets-Sheet 3 DISSOLVINGURANIUM' METAL DEPOSITED ON STAINLESS STEEL COLLECTOR IN CONDENSA TE ANDMAKE UP (I) HNO; 0!? (2)HC/ 8 H 0 on (3)1450 & H 0

coNoENslN s WA 75/? VAPOR EVAPORATING CONCENTRATED SOLUTION SOLUTION U0Fe +4-4- c TO FU RTHER TREATMENT INVENTORS James M. Carter BY ClarenceE. Larson ATTORNEY.

Oct. 7, 1958 J. M. CARTEIR ETAL PROCESS OF RECOVERING URANIUM Filed001;. 20, 1944 s Sheets-Sheet 4 STARTING SOLUTION MATERIAL 2 FROM PRIOR2: 11 TREATMENT F/LTRA TE PRECIPITATIN G ZNH40H AND FILTERING PREC/P/TA75.5

I (N )z 2 7 FEZOH): 040/1) 22%;- DISSOLVING To DISCARD OR SALVAGESOLUTION v 0 Fe Cr-f-f-I- //-Fe+++ 5 3% pp,q0x lFFe 3% APPROX.

G COMPLEXIN G LACT/C AC/D Fe +'H" ACET/C ACID FLUOR/DE NULLAPON v ADJ UST I N G H L0 3.0

"" AND coo LING @515 N, +4- Cr Fe PRECIPITAT IN G 1 ZHZOZ AND FILTERINGA T0 DISCARD OR SALVAGE CALCINING PRE C/P/ T A TE U04- GAS TO FU RTH ERTREATMENT INVENTORS James M. Carter Clarence E. Larson ATTORNEY.

Oct.f7, 1958; J. M. CARTER ETAL 2,855,270

' PROCESS OF RECOVERING URANIUM Filed Oct. 20, 1944 5 Sheets-Sheet sSTARTIN G MATERIAL FROM PRIOR TREATMENT V v GASES GASES REDUCINGQREAC'TING CH4. 32 00 Q Clg a uc/ GASES r REAc-rm coma CALCINING GAS- cm28 a .Cla

u :/.,l v -u c/ RES/DUE U02 UOC/ SUBLIMING IN 'VACUQM TQ SALVAGE8UBL/MATE'UC/4 END PRODUCT INVENTORS James M. Carter BY I Clarence E.Larson ATTORNEY.

nited States Patent PROCESS OF RECOVERING URANIUM James M. Carter,Pasadena, Calif., and Clarence E. Larson, Oak Ridge, Tenn., assignors tothe United States of America as represented by the United States AtomicEnergy Commission Application October 20, 1944, Serial No. 559,624

8 Claims. (Cl. 2314.5)

The present invention relates to processes of producing uranium and moreparticularly to improvements in certain steps of the process disclosedin the copending application of James M. Carter and Martin D. Kamen,Serial No. 532,159, filed April 21, 1944, now Patent No. 2,758,006.

It is an object of the invention to provide an improved process ofreclaiming uranium from a calutron.

Another object of the invention is to provide an improved process ofrecovering the residue of an uranium compound which has been subjectedto treatment in a calutron from the parts of the calutron disposed inthe source region thereof upon which the residue is deposited.

Another object of the invention is to provide an improved process ofrecovering metallic uranium from the collector of a calutron upon whichthe enriched metallic uranium is deposited.

A further object of the invention is to provide an improved process ofpurifying uranium which has been recovered from a calutron.

A still further object of the invention is to provide a process ofreclaiming uranium from a wash solution derived from a calutron, inwhich the uranium is precipitated as uranium peroxide away from metalimpurities in the wash solution.

The invention, both as to its organization and method of operation,together with further objects and advantages thereof, will best beunderstood by reference to the following specification taken inconnection with the accompanying drawings in which Figure 1 is aperspective View, partly broken away, of a calutron in conjunction withwhich there may be carried out the process of the present invention;Fig. 2 illustrates a portion of the flow diagram of the present process,indicating the recovery of the residue of UCL, from the parts of thecalutron disposed in the source region thereof upon which it isdeposited; Fig. 3 illustrates another portion of the flow diagram of thepresent process, indicating the recovery of the metallic uranium fromthe collector of the calutron upon which it is deposited; Fig. 4illustrates a further portion of the flow diagram of the presentprocess, indicating the purification of the recovered uranium; and Fig.5 illustrates a still further portion of the flow diagram of the presentprocess, indicating the ultimate conversion of the purified uranium backto UCl At the outset, it is noted that a calutron is a machine of thecharacter of that disclosed in the copending application of Ernest 0.Lawrence, Serial No. 557,784, filed October 9, 1944, now Patent No.2,709,222, and is employed to separate the constituent isotopes of anelement and more particularly to increase the proportion of a selectedisotope in an element containing a plurality of isotopes in order toproduce the element enriched with the selected isotope.

Such a calutron essentially comprises means for vaporizing a quantity ofmaterial containing an element which is to be enriched with a selectedone of its several isotopes; means for subjecting the vapor to,ionization, whereby at least a portion of the vapor is ionized causingions of the several isotopes of the element to be produced; electricalmeans for segregating the ions from the un-ionized vapor and foraccelerating the segregated ions to relatively high velocities;electromagnetic means for deflecting the ions along curved paths, theradii of curvature of the paths of the ions being proportional to thevsquare roots of the masses of the ions, whereby the ions areconcentrated in accordance with their masses; and.

means for de-ionizing and collecting the ions ofthe selected isotopethus concentrated, thereby to produce a deposit of the element enrichedwith the selected isotope.

Referring now more particularly to: Fig. 1, there is illustrated arepresentative example of a calutron. 10 of the character noted, whichcomprises magnetic field structure including upper and lower pole pieces11 and 12,, provided with substantially fiat parallel spaced-apart polefaces, and a tank 13 disposed between the Pole facesof the pole pieces11 and 12. The pole pieces 11- and 12 carry windings, not shown, whichare adapted to be energized in order to produce a substantially uniformand relatively strong magnetic field therebetween, which magnetic fieldpasses through the tank 13 and the various parts housed therein. Thetank 13 is of tubular configuration, being substantially crescent-shapedin plan, and comprising substantially flat parallel spaced-apart top andbottomwalls 14 and 15, upstanding. curved inner and outer Walls16 and17, and end Walls 18 and 19. The end Walls 18v and 19 close the.opposite ends of the tubular tank 13 and are adapted to be removablysecured in place, whereby the tank 13 is hermetically sealed. Also,vacuumpumping apparatus, not shown, is. associated with the tank13,,whereby theinteriorof the tank 13 may be evacuated to a pressure ofthe order of 10- to-10- mm. Hg. Preferably, the component parts of thetank 13 are formed of steel, the bottom wall 15 thereof resting directlyupon thepole face of the lower pole piece 12,, and the top wall. 14thereof. being spaced at suitable distance from the pole face of theupper. pole piece 11, whereby the top and bottom walls. 14- and 15constitute in effect pole pieces with respect to the interior of thetank 13, as explained more fully hereinafter.

Thev removable end wall 18 carries an insulator 20 which supports anupstanding charge block 21,.provided with a hollow central cavity 22constituting a charge receiving pocket. surrounded by rather thick sidewalls. Electrical heating elements 23 are embedded in the side walls ofthe charge block 21 and are adapted to be connected to a suitable sourceof current, whereby the charge block 21 may bev appropriately heated,the charge block 21 being formed of cast steel or the like. Also, thecharge block 21 is provided with a removable cover, not shown, andsupports a tubular member 24 which in turn supports an arc block 25formed of carbon or graphite.v The are block 25 is substantiallyC-shaped in plan, an upstanding slot 26 being formed in the wall thereofremote from the charge block 21. Thus, the arc block 25 is of hollowconstruction, having a central are cavity 27 formed therein, the arccavity 27 formed in the are block 25 communicating through the tubularmember 24 with the cavity 22 formed in the charge block 21.

Also, the removable end wall 18. carries an insulator 28, disposed abovethe insulator 20, which supports horizontally projecting cathodestructure 29, including a filaa mentary cathode 30 adapted to beconnected to a suitable source of current. The cathode structure 29projects over the upper end of the charge block 21, whereby thefilamentary cathode 30 overhangs and is aligned with respect to theupper end of the cavity 27 formed in the arc block 25. Further, an anode31 is arranged below and in alignment. with respect to the lower end ofthe cavity 27 formed Patented Oct. 7, 1958 in the arc block 25, theanode 31 beingsupported by the charge block 21. The filamentary cathode30 and the cooperating anode 31 are adapted to be connected to asuitable source of current; j

Ion accelerating structure, including a pair of upstandmgplates 32formed of carbon or graphite, is supported by insulating structure, notshown, carried by the removable end wall 18. The pair of upstandingplates 32 are arranged in spaced-apart relation in order to define aslit33 therebetween, arranged in substantial alignment with respect to theslot 26 formed in the wall of the arc block 25. A suitable source ofvoltage is adapted to be connected between the arc block 25 and the ionaccelerat- 1ng structure, including the plates 32, for a purpose morefully explained hereinafter.

The removable end wall 19 carries an insulator 34 which supports anupstanding collector block 35 formed of stainless steel or the like andprovided with two laterally spaced-apart cavities or pockets 36 and 37which communicate with aligned slots 38 and 39 formed in the wall of thecollector block 35 disposed remote from the removable end wall 19.Alternatively, the collector block may be fabricated of steel plate andthe inner surfaces of the pockets 36 and 37 lined with stainless steelplates. It is noted that the pockets 36 and 37 are adapted to receivetwo constituent isotopes of an element which have been separated in thecalutron 10, as explained more fully hereinafter. Finally, the innerwall 16 carries a number of insulators 40 which support a tubular liner41 formed of copper or the like, rectangular in vertical cross-section,disposed within thetank 13 and spaced from the walls 14, 15, 16 and 17thereof. One end of the tubular liner 41 terminates adjacent theaccelerating structure, including the plates 32; and the other end ofthe tubular liner 41 terminates adjacent the collector block 35; thetubular liner 41 constituting an electrostatic shield for thehighvelocity ions traversing the curved paths between the slit 33 formedby the plates 32 of the ion accelerating structure and the slots 38 and39 formed in the collect-or block 35, as explained more fullyhereinafter.

In view of the above description, it will be understood that the partsof the calutron 10 carried by the removable end wall 18 constitute asource unit, and the end of the tank 13 disposed adjacent the sourceunit constitutes the source region of the calutron. Similarly, the partsof the calutron carried by the removable end wall 19 constitute acollector unit, and the end of the tank 13 disposed adjacent thecollector unit constitutes the collector region of the calutron.

Considering now the general principle of operation of the calutron 10, acharge comprising a compound of the element to be treated is placed inthe charge pocket 22 in the charge block 21, the compound of the element:1 a mentloned being one WhlCh may be readlly vaporized. The cover, notshown, is then secured on the charge block 21 and the end walls 18 and19 are securely attached to the open ends of the tank 13, whereby thetank 13 is hermetically sealed. The various electrical connections arecompleted and operation of the vacuum pumping apparatus, not shown,associated with the tank 13 is initiated. When a pressure of the orderof 10" to mm. Hg is established within the tank 13, the electriccircuits for the windings associated with the pole pieces 11 and 12 areclosed and adjusted, whereby a predetermined magnetic field isestablished therebetween, traversing the tank 13. The electric circuitfor the heating elements 23 is closed, whereby the charge in the chargepocket 22 in the charge block 21 is heated and vaporized. The vaporfills the charge pocket 22 and is conducted through the tubular member24 into the cavity 27 formed in the arc block 25. The electric circuitfor the filamentary cathode 30 is closed, whereby the filamentarycathode 30 is heated and rendered electron-emissive. Then the electriccircuit between the filamentary cathode 30 and the anode 31 is closed,whereby an arc discharge is struck therebetween,

4 electrons proceeding from the filamentary cathode 30 to the anode 31.The electrons proceeding from the filamentary cathode 30 to the anode 31break up the molecular form of the compound of the vapor to aconsiderable extent, producing positive ions of the element which is tobe enriched with a selected one of its isotopes.

The electric circuit between the arc block and the ion acceleratingstructure, including the plates 32, is completed, the plates 32 being ata high negative potential with respect to the arc block 25, whereby thepositive ions are attracted and accelerated to the voltage impressedbetween the arc block 25 and the ion accelerating structure. Moreparticularly, the positive ions proceed from the interior of the cavity27 formed in the arc block 25, through the slot 26 formed in the wallthereof, and across the space between the plates 32 and the adjacentwall of the arc block 25, and thence through the slit 33 formed betweenthe plates 32 into the interior of the tubular liner 41. Thehigh-velocity positive ions form a vertical upstanding ribbon proceedingfrom the cavity 27 formed in the arc block 25 through the slot 26 andthe aligned slit 33 into the tubular liner 41.

The collect-or block 35, as well as the tubular liner 41, iselectrically connected to the ion accelerating structure, including theplates 32, whereby there is an electric field-free path for the highvelocity positive ions, disposed between the plates 32 and the collectorblock 35 within the tubular liner 41. The high-velocity positive ionsentering the adjacent end of the liner 41 are deflected from theirnormal straight-line path and from a vertical plane, passing through theslot 26 and the slit 33, due to the efiect of the relatively strongmagnetic field maintained through the space within the tank 13 and theliner 41 through which the positive ions travel, whereby the positiveions describe arcs, the radii of which are proportional to the squareroots of the masses of the ions and consequently of the isotopes of theelement mentioned.

Thus, relatively light ions, a relatively light isotope of the element,describe an interior arc of relatively short radius and are focusedthrough the slot 38 into the pocket 36 formed in the collector block 35;whereas relatively heavy ions, a relatively heavy isotope of theelement, describe an exterior arc of relatively long radius and arefocused through the slot 39 into the pocket 37 formed in the collectorblock 35. Accordingly, the relatively light ions are collected in thepocket 36 and are de-ionized to produce a deposit of the relativelylight isotope of the element therein, while the relatively heavy ionsare collected in the pocket 37 and are de-ionized to produce a depositof the relatively heavy isotope of the element therein.

After all of the charge in the charge pocket 22 formed in the chargeblock 21 has been vaporized, all of the electric circuits areinterrupted and the end wall 18 is removed so that another charge may beplaced in the pocket 22 and subsequently vaporized in the mannerexplained above. After a suitable number of charges have been vaporizedin order to obtain appropriate deposits of the isotopes of the elementin the pockets 36 and 37 of the collector block 35, the end wall 19 maybe removed and the deposits of the collected isotopes in the pockets 36and 37 in the collector block 35 may be reclaimed.

Of course, it will be understood that the various dimensions of theparts of the calutron 10, the various electrical potentials appliedbetween the various electrical parts thereof, as well as the strength ofthe magnetic field between the pole pieces 11 and 12,- are suitablycorrelated with respect to each other, depending upon the mass numbersof the several isotopes of the element which is to be treated therein.By way of illustration, it is noted that when the calutron 10 isemployed in order to produce uranium, the compound of uranium which issuggested as a suitable charge in the charge block 21 is UCl as thiscompound may be readily vaporized and the molecular form of the vapormay be readily broken up to formpositive ions of uranium with greatfacility.

More particularly, the minor fraction of the UCL; vapor is ionized toform positive atomic ions including U+, U++, Cl+ and Cl++; and positivemolecular ions including C1 Cl UCl UCl UCl UCl UCI UCl UCl+ and UCl++.Of these atomic and molecular ions only the singly ionized atomic ionsU+ have the required ratio between mass and charge such that they arefocused through the slots 38 and 39 into the pockets 36 and 37 formed inthe collector block 35; the atomic ions U+ of masses 234 and 235focusing through the slot 38 into the pocket 36, and the atomic ions U+of mass 238 focusing through the slot 39 into the pocket 37, aspreviously noted.

The doubly ionized atomic ions U have such a ratio between mass andcharge that they are deflected along an arc of shorter radius intoengagement with the inner Wall of the liner 41, where they arede-ionized to form a deposit thereon. The singly and doubly ionizedatomic ions Cl+ and Cl++ and the singly and doubly ionized molecularions C1 and Cl have such small ratios between mass and charge that theyare deflected along arcs of very short radii into engagement with theinner wall of the liner 41 adjacent the source region, where they arede-ionized to form neutral chlorine molecules, which gas is subsequentlypumped from the tank 13 due to the operation of the vacuum pumpingapparatus previously noted. Similarly, the doubly ionized molecular ionsUCl UCl UCl and UCl have intermediate ratios between mass and chargesuch that they are deflected along arcs of intermediate radii intoengagement with the inner wall of the liner 41 intermediate the sourceregion and the collector region, where they are de-ionized to form adeposit thereon. Finally, the singly ionized molecular ions UCl UCl UCland UCl+ have large ratios between mass and charge, such that they aredeflected along arcs of large radii into engagement with the outer wallof the liner 41 intermediate the source region and the collector region,where they are de-ionized to form a deposit thereon.

The residue of U01 deposited on the parts of the calutron disposed inthe source region thereof, principally upon the liner, is recovered by awater wash process, whereby various impurities including copper, iron,chrornium, nickel and carbon are introduced in the wash solution, due tothe fact that the various parts of the calutron which are thus washedwith water are formed of the materials mentioned.

Considering now the details of the recovery of the UCL, residue from theparts of a calutron disposed in the source region thereof, reference ismade to'the portion of the flow diagram illustrated in Fig. 2. The partsof the calutron disposed in the source region thereof, principally thesource-region end of the liner, are scrubbed and washed with hot water,whereby the residue of UCL, deposited thereon is dissolved; and variousimpurities, including copper, iron, chromium, nickel and carbon, areintroduced in the water wash, due to the fact that the various parts ofthe calutron which are thus washed with hot water are formed of thematerials mentioned. The wash water is then sieved in order to removeany solid impurities which may be picked up, such, for example, as smallpieces of metal and carbon. These solid impurities may be eitherdiscarded or subjected to salvage treatment in order to recover anyoccluded uranium. The sieved wash. water is then treated with H byadding a slight excess of ten percent H 0 and agitating the solution inorder to oxidize the various contained materials. For

example, the wash water prior to the step of oxidation 6 the uranium isput in solution as uranyl ion, suspended copper is put in solution ascupric ion, and other dissolved materials are putin their higher stablevalence states if they are not already in such state. Carbon is notoxidized by this treatment. The effect of the oxidation on the variousmaterials contained in the wash solution maybe indicated as follows:

Accordingly, the oxidized wash water contains at least the following: UOCu++, Fe+++, Cr+++, Ni++ and C (carbon). The oxidized wash water is thenfiltered in order to remove C which may be discarded or subjected tosalvage treatment in order to recover any occluded uranium.

In the event this filtrate is rather dilute, it may be concentrated byevaporation; otherwise this step is omitted. In the event the filtrateis concentrated by evaporation, the water vapor which is driven off iscondensed and to it is added enough makeup water in order to provide anew wash solution, which is used again to wash the parts of the calutrondisposed in the source region thereof, in the manner previouslyexplained. This step, comprising condensing and re-using the water vaporwhich is driven off the filtrate incident to concentration byevaporation, is advantageous in view of the fact that any uraniumentrained in the water vapor is not lost to the outside. The originalfiltrate mentioned above, or the concentrated filtrate followingevaporation, in the event this step is employed, is then stored forfurther treatment.

Considering now the details of the recovery of the metallic uranium,reference is made to the portion of the flow diagram illustrated in Fig.3. The inner surfaces of the first pocket of the collector of thecalutron are etched with one of a number of acid solutions, whereby thedeposit of metallic uranium is dissolved; and variout impuritiesincluding iron, chromium and nickel are introduced in the acid washsolution, due to the fact that the inner surfaces of the first pocket ofthe collector of the calutron which are thus etched with the acidsolution are formed of stainless steel which comprises the materialsmentioned. Accordingly, the wash acid contains at least the followingions:UO Fe+++, Cr+++, and Ni++.

A suitable acid wash solution which may be employed for the purposementioned comprises an aqueous solution containing HNO (approximately12%). Another suitable acid wash solution comprises an aqueous solutioncontaining HCl (approximately 2%) and H 0 (approximately 0.5%). Afurther suitable acid wash solution comprises an aqueous solutioncontaining H (approximately 18%) and H 0 (approximately 10%). Thus, itwill be understood that the first acid wash solution comprises anoxidizing acid, whereas the second and third acid wash solutionscomprise a separate oxidizing agent in the form of H 0 Hence, the acidwash solution employed in any case produces an oxidizing effect uponboth the uranium and the metal impurities which are dissolved therein.

In the event the wash acid is rather dilute in the ions mentioned, itmay be concentrated by evaporation; otherwise this step is omitted. Inthe event the wash acid is concentrated by evaporation, the vapor whichis driven off is condensed and to it is added enough makeup HNO or HCland H 0 or H 80 and H 0 depending upon the composition of the originalwash acid employed, in

greater than approximately 3%.

order to provide a new Wash acid'which is again used to wash the firstpocket of the collector of the calutron,

' in the manner previously explained. This step, compristhe followingions: UO tt, Cut- Pe Cr+++, and

Ni reference is made to the portion of the flow dia gram illustrated inFig. 4. In the event that the solution contains a reasonablylargeifamountof copper. and nickel,

the solution is subjected to "a preliminary ammonia treatmentin order toeliminate a majority, if not substantially all, of the impuritiesmentioned; otherwise. this step is omitted. Assuming that the ammoniatreatment is to be employed, the solution is treated either with excessNH gas or carbonate-free .NH OH, whereby (N1-I U O Fe(OH) and Cr(OH) areprecipitated away from most of the copper and nickel in solution in theformof ammonia complex ions, Cu(l II-I and droxide and, chromichydroxide, is, washed with water containing about 1% NH OH and 1% NH NO'in order,

to eliminate occluded copper and nickel ammonia, complex ions. Thefiltrate containing'the copper and nickel ammonia complex ions is thendiscarded or. subjected to salvage treatment in order to recover anyuranium contained; and the initially purified precipitate of Thesolution is then filtered and the precipitate, consisting of ammoniumdiuranate, ferric hyvapor are given off incident to the reduction.

that the Fe+++ ion content of the solution mentioned is greater thanapproximately 3% the ferric ion in the solution is complexed by theintroduction of an agent which forms complex ion with ferric ion; on theother hand, in the event it is determined that the Fe+++ contained isless than approximately 3%, the last mentioned 1 treatment is omitted.Assuming that the solution contains greater than approximately 3% Peion, this ion is complexed by the addition to the solution of anappropriate agent such as lactic acid, acetic acid, fluoride ion, orNullapon. tioned to the solution complexes the ferric ion, therebyeliminating the normal catalytic action of the ferric ion upon H 0 andconsequently catalytic decomposition of the hydrogen peroxide in thesubsequent purification. It will be understood that the presence of anappreciable amount of uncomplexed ferric ion in the solution will affectcatalytic decomposition of hydrogen peroxide, thereby preventingcomplete precipitation of uranium peroxide, as explained more fullybelow.

Now assuming that a solution is obtained that contains UO Cu++, Ni++,Cr+++, and Fe+++ ions, which is conditioned for purification by thehydrogen peroxide precipitation step, this solution may be an originalwash solution or a solution which has been derived after preliminaryammonia treatment, as explained above; either of which solutions may ormay not have been treated with the ferric ion complexing agent. In anycase, the solution does not contain undue amounts of copper or nickelimpurities or uncomplexed ferric ion in an, amount tioned is fairly acidin view of its derivation and the pH The addition of the agent men- 5 iThe solution menesses into crude UCl thereofisj adjusted within-theapproximate range 1.0 to 3.0, and preferably within the range 1.5 to3.0, by the addition of NH OI-I thereto. The acidified solution is thencooled to a temperature in the range of about 0 to 10 C.,' andpreferably to approximately 5 C., and hydrogen peroxide, which mayconveniently be in'the form of a 30% solution of H 0 is added to thesolution in excess, so that there is more than enough H 0 to precipitateall of the uranium as the peroxide, UO -2H O.

The solution is kept cool'and is permitted to remain in a quiescentstate until substantially complete settling of the uranium peroxide hastaken place. Thereafter, the solution is filtered and the precipitate iswashed with an aqueous solution that is approximately 2% in NH NO and 3%in H 0 The filtrate containing the copper, nickel, chromium and ironimpurities is then discarded or subjected to salvage treatment in :orderto recover any uranium contained and the purified UO -2H O precipitateis calcined to U0 at approximately325 0., whereby 0 gas isgiven offincident to the calcination. The purified uranium in the compound formU0 is then stored for further treatment or commercial use, as previouslynoted.

Considering now the details of the ultimate conversion of the batch ofU0 to UClr, reference is made to the portion of the tlowdiagramillustrated in Fig. 5. The uranium trioxide may be converted .byalternative proc- In accordance with one process the U0 is finst reducedtoUO by heatingwith CH at approximately 450 C., whereby CO CO gases andwater The uranium dioxide is then reacted with C01, in the vapor phaseat approximately 450 C. in a suitable'reaction chamber in order toproduce crude UCL whereby COC1 CO CO and C1 gases are given off incidentto the reaction. In accordance with an alternative process the U0 may bereacted directly with CCL; in the liquid phase in an autoclave at atemperature of approximately to C. and at a pressure of approximately200 pounds per square inch gauge in order to produce U01 whereby COCl COCO and C1 gases are given off incident to the reaction. The uraniumpentachloride thus produced is then calcined or decomposed to producecrude UCl by heating to approximately 350 C., whereby C1 gas is givenoff incident to the calcination.

In any case, the crude uranium tetrachloride produced by either of thealternative processes indicated above is then sublimed in a suitablemolecular still at approximately 600 C. in order to produce a sublimateof UCl whereby residues of U0 and UOCI are produced incident to thesublimation. The residues of U0 and UOCl are ultimately converted to UClThe UCL, thus produced is of very pure form.

The present process of recovering uranium from solutions is veryeffective in view of the fact that it is quite versatile. Thus, not onlymay uranium be reclaimed from a solution containing the impuritiesmentioned, copper, iron, chromium and nickel, but the solution maycontain a variety of other impurities, such as manganese and zinc,without adversely affecting the purification. Moreover, the purificationcan be carried out as explained without particular reference to theidentification of the impurities or the proportions contained in thewash solution; this feature is very advantageous in view of the factthat both the particular impurities as well as the related quantitiesthereof vary considerably among the different solutions derived from thedifferent calutrons.

In view of the foregoing it is apparent that there has been provided animproved process of recovering, reclaiming. purifying and convertinguranium, both in metallic and compound form on a large scale incommercial quantities.

Also, it will be understood that the present process may be suitablymodified so that a compound of uranium other 9 than UCL; may be treatedin the calutron. For example, the calutron, as well as the conversionsteps of the process, may be modified, whereby UCl UBr etc. may betreated.

While there has been described what is at present con sidered to be thepreferred embodiment of the invention, it will be understood thatvarious modifications may be made therein and it is intended to cover inthe appended claims all such modifications as fall within the truespirit and scope of the invention.

What is claimed is:

1. The process for recovering uranium values from deposits formed on ametallic surface comprising treating said deposits to produce anoxidized acidic solution containing the uranium together with impuritiesof the group consisting of copper, iron, chromium, nickel, manganese andzinc, adjusting the pH of the solution within the approximate range 1.5to 3.0, treating the acid solution with hydrogen peroxide to precipitatethe uranium as uranium peroxide away from the metal impurities in thesolution, separating the uranium peroxide precipitate from the metalimpurities in the filtrate, and then calcining the uranium peroxideprecipitate to produce uranium trioxide.

2. The process for recovering uranium values from deposits formed on ametallic surface comprising treating said deposits to produce anoxidized acidic solution containing the uranium together with impuritiesof the group consisting of copper, iron, chromium, nickel, manganese andzinc, treating said solution with ammonia to precipitate the uranium andthe iron and chromium away from the other metal impurities which remainin the solution, separating the precipitate from the solution,dissolving the precipitate in acid, whereby the solution contains uranyland ferric and chromic ions, adjusting the pH of the solution within theapproximate range 1.5 to 3.0, treating said solution with hydrogenperoxide to precipitate the uranium as uranium peroxide away from theiron and chromium impurities in the solution, and then separating theuranium peroxide precipitate from the solution.

3. In a process for recovering uranium values from deposits formed on ametallic surface, the steps comprising producing from said deposits anoxidized acidic solution containing lsaid uranium values together withimpurities including at least one material selected from the groupconsisting of copper, iron, chromium, nickel, manganese and zinc,adjusting the pH of the solution to within the range 1.0 to 3.0, thenadding hydrogen peroxide 10 to the solution to precipitate the uraniumas uranium peroxide away from the impurities in the solution, andseparating the uranium peroxide from the solution.

4. The process for recovering the uranium values from deposits formed ona metallic surface containing materials :of the group consisting ofcopper, iron, chromium, nickel, manganese and Zinc, comprising treatingsaid deposits with an oxidizing acidic solvent to produce a solutioncontaining the uranium together with said materials as impurities,adjusting the pH of the solution to the range of about 1.0 to 3.0,cooling the solution to a temperature in the range of about 0 to 10 C.,then precipitating the uranium as uranium peroxide away from theimpurities in the solution by the addition of hydrogen peroxide, andseparating the uranium peroxide from the solution.

5. in a process of recovering uranium values from deposits formed on ametallic surface including the steps of producing an oxidized acidicsolution containing the uranium together with impurities including morethan about 3% of ferric ion, adjusting the pH of the solution to therange of about 1.0 to 3.0, precipitating the uranium as uranium peroxideaway from the impurities in the solution by means of hydrogen peroxide,and separating the uranium peroxide from the solution; the stepcomprising, complexing the iron in the solution prior to saidprecipitation step to prevent the ferric ion catalyzed decomposition ofthe hydrogen peroxide employed therein.

6. The process as defined in claim 3, wherein said deposits comprise theresidue of a water-soluble uranium compound formed with a metallicsurface, and, in which,

water is the solvent employed in producing said oxidized acidicsolution.

7. The process as defined in claim 3, wherein said deposits comprise theresidue of uranium tetrachloride formed on a metallic surface, and, inwhich, water is the solvent employed in producing said oxidized acidicsolution.

8. The process as defined in claim 4, wherein said deposits comprisemetallic uranium deposits formed with said metallic surface.

References Cited in the file of this patent Fairley: Journal of theChemical Society, vol. 31, pp. 127-443 (1877).

Rosenheim et al.: Uranium Tetroxide Dihydrate, Chemical Abstracts, vol.23, p. 4634 (1929).

2. THE PROCESS FOR RECOVERING URANIUM VALUES FROM DEPOSITS FORMED ON AMETALLIC SURFACE COMPRISING TREATING SAID DEPOSITS TO PRODUCE ANOXIDIZED ACIDIC SOLUTION CONTAINING THE URANIUM TOGETHER WITH IMPURITIESOF THE GROUP CONSISTING OF COPPER, IRON, CHROMIUM, NICKEL, MANGANESE ANDZINC, TREATING SAID SOLUTION WITH AMMONIA TO PRECIPITATE THE URANIUM ANDTHE IRON AND CHROMIUM AWAY FROM THE OTHER METAL IMPURITIES WHICH REMAININ THE SOLUTION, SEPARATING THE PRECIPITATE FROM THE SOLUTION,DISSOLVING